An organic light-emitting diode device, also called an OLED device, commonly includes a substrate, an anode, a hole-transporting layer made of an organic compound, an organic luminescent layer with suitable dopants, an organic electron-transporting layer, and a cathode. OLED devices are attractive because of their low driving voltage, high luminance, wide-angle viewing, and capability for full-color flat emission displays. Tang et al. described this multilayer OLED device in their U.S. Pat. Nos. 4,769,292 and 4,885,211.
A common problem with OLED displays is sensitivity to moisture. They can be particular highly moisture-sensitive electronic devices, and require humidity control to levels below about 1000 ppm and some require humidity control below even 100 ppm. Often, an encapsulation container encloses the OLED device and is secured to the substrate to form an enclosure. Desiccant material is formed on the inside surface of the enclosure to protect the OLED from moisture. A problem with this arrangement is that stress can be transferred between the substrate and the encapsulation container thereby causing mechanical damage to either or either of such elements (e.g. cracking) or to the adhesive used to secure the substrate and encapsulation container (e.g. delamination or cracking). This is particularly a problem as the OLED displays become larger and can flex during handling. This can also be a problem when the substrate and the encapsulation container comprise different materials with different coefficients of expansion.